Method of making vane tracks for hydrodynamic machines



W. FERRIS Feb. 10, 1953 METHOD OF. MAKING VANE TRACKS FOR HYDRODYNAMIC MACHINES 2 SHEETS-SHEET 1 Filed NOV. 9, 1946 INVENTOR WALTER FERRIS ATTORNEY Feb- 10, 1953 w. FERRIS 2,627,650

METHOD OF MAKING VANE TRACKS FOR HYDRODYNAMIC MACHINES Filed Nov. 9, 1946 2 SHEETSSHEET 2 37/ INVENTOR WALTER F ERRI 5 WW ATTORNEY Patented Feb. 10, 1953 IVIETHOD OF MAKING VANE TRACKS FOR HYDRODYNAMIC MACHINES Walter Ferris, Milwaukee, Wis., assignor to The Oilgear Company, Milwaukee, Wis., a corporation of Wisconsin Application November 9, 1946, Serial No. 709,019

2 Claims. (Cl. 29-156.8)

This invention relates to variable displacement hydrodynamic machines of the slidable vane type and more particularly to the vane track of such a machine.

A slidable vane type hydrodynamic machine includes a rotor having a plurality of vane slots extending inward from its periphery, a vane slidable in each slot, two cheek plates which are closely fitted to opposite sides of the rotor and to opposite edges of the vanes, a spacer ring which extends around the rotor and forms with the cheek plates a chamber having a plurality of ports through which liquid flows to and from the space between the rotor and the spacer ring, and a vane track upon which the outer ends of the vanes slide during rotation of the rotor.

The vane track includes a plurality of abutments or bridges, with which the vanes coact to provide substantially liquid tight seals between the inlet and outlet ports of the machine, and a plurality of track sections which are arranged between the bridges and form therewith a continuous track. The bridges are ordinarily arranged in pairs with one bridge of each pair arranged close to the periphery of the rotor and with the other bridge spaced from the periphery of the rotor when the machine is performing useful work, the bridge which is close to the rotor being called the sealing bridge and the bridge which is spaced from the rotor being called the pumping bridge or the working bridge. If all the bridges are stationary, the displacement of the machine is constant but the displacement may be varied by providing means to move the working bridge :of each pair toward and from the rotor.

Vane type hydrodynamic machines are extensively used as pumps but a properly designed vane type hydrodynamic machine may function as a motor. When the machine is used as a pump its rotor is ordinarily rotated at such a high speed that the centrifugal force is sufficient .to keep the vanes in contact with the track and it is only necessary to hydrostatically balance the vanes. However, if the machine is operated at slow speeds, as by being used as a motor, the centrifugal force is insufficient to keep the vanes in contact with the track in which case the machine is provided with suitable means for positively moving the vanes outward such as means for supplying high pressure liquid to the inner ends of the outward moving vanes.

When the working bridges of a machine havin two pairs of bridges are spaced from the rotor and the rotor is rotated, each vane will move inward as its outer end moves from a working bridge toward the adjacent sealing bridge, it will move outward as its outer end moves from the sealing bridge toward the next working bridge, it will move inward as its outer end moves from that bridge toward the next sealing bridge, and it will move outward as its outer end moves from that sealing bridge toward the first mentioned bridge. Each vane thus makes two reciprocations during each revolution of the rotor and, since the rotor is often driven at very high speeds, the reciprocations may be very rapid.

If the track is so shaped that it forces each vane inward too rapidly, the vane will tend to dig into the track and thus cause excessive wear of the track or the vane or both. If the slope of the track at any point is so steep that an outward moving vane cannot follow it, the vane may leave the track at that point and reengage the track at another point with an impact that tends to damage both the'track and the vane. Consequently, the'shape of the track must be such as to provide gradual accelerations and decelerations of the vanes.

I A track having a surface so shaped as to cause uniform accelerations and decelerations of the vanes would provide an ideal condition which may be approached in a unitary rigid vane track for a constant displacement machine but in a variable displacement machine the contour of the track will vary as the movable bridges are'moved inward and outward to vary the displacement.

It has heretofore been proposed to provide vane tracks having flexible track sections fixed to the movable bridges but such prior vane tracks are so expensive to make that they are impractical for commercial use.

The present invention has as an object to provide a method of making a vane track having a plurality of movable bridges, a plurality of stationary bridges and flexible track sections fixed to the movable bridges and so constructed and supported that in all positions of the movable bridges they will form with the bridges an endless track of a contour that will cause gradual accelerations and decelerations of the vanes in their radial movements.

Other objects and advantages will appear from the following explanation of methods of making the vane track sections and from the following description of the vane track shown in the accompanying drawings in which the views are as follows:

Fig. 1 is a transverse section through one half of a hydrodynamic machine having a vane track in which the invention is embodied, the view being taken along the faces of the rotor and the spacer ring and showing the movable bridge in zero displacement position.

Fig. 2 is a similar section through the other half of the same machine and shows the movable bridge in maximum displacement position.

Fig. 3 is a view of the inner face of one of the stationary bridges shown in Figs. 1 and 2.

Fig. 4 is an end view of the bridge shown in Fig. 3.

Fig. 5 is a side view of one of the movable bridges and the two flexible track sections formed integral therewith.

Fig. 6 is an end view of the parts shown in Fig. 5.

Fig. 7 is a view illustrating a method of making from a rectangular blank a partly finished blank from which the bridge and track sections shown in Fig. 5 may be made.

Fig. 8 is a diagrammatic view illustrating how the partly finished blank of Fig 7 may be formed into the shape shown in Fig. 5.

Fig. '9 is a view illustrating another method of making from a rectangular blank a partly finished blank from which the bridge and track sections shown in Fig. 5 may be made.

The hydrodynamic machine shown in Figs. 1 and 2 is of the general type of the machine shown in Patent No. 2,141,170 to which. reference may be had for details of construction. It is deemed suf- .ficient to state herein that the machine has a rotor I fixed for rotation with a shaft 2 and arranged within a spacer ring 3, that rotor I has .a plurality of vane slots 4 extending inward from its periphery and a vane 5 slidable in each slot with its edges flush with the faces of rotor I, that two cheek plates (not shown) engage opposite faces of spacer ring 3 which is just enough thicker than rotor I to provide running clearance between rotor l and the inner faces of the cheek plates, and that two diametrically opposed ports 6 and two diametrically opposed ports I communicate with the spaces between rotor I and the inner periphery of spacer ring 3.

The outer ends of vanes 5 ride upon an endless vane track comprising two stationary sealing bridges 8 which are fixed in spacer ring 3 diametrically opposite each other and have their in- .ner faces arranged close to the periphery of rotor I, two movable working bridges 9 which are spaced 90 from bridges 8 and are .slidable in spacer rings 3 toward and from rotor I, and four flexible arcuate track sections Ii) each of which is formed integral with a movable bridge 9 and extends therefrom to the adjacent stationary bridge 8.

As shown in Figs. 3 and 4, each bridge 8 includes a body portion I I having two integral extensions I2 on each end thereof and four abutments I3 each of which is closely fitted against an end face of body portion I I and against a side face of an extension I2. Abutments I3 are rigidly secured in position by two pins I4 each of which is closely fitted in an extension I2 and in the two adjacent abutments I3 and which may be fixed in position by slightly upsetting its ends. Each bridge 8, including its abutments I3, is exactly the same thickness as spacer ring 3 and is tightly fitted in a recess I5 formed in the spacer ring 3.

The inner face I6 of body portion II is accurately and smoothly finished to a radius which preferably is equal to the distance between face I I5 and the center of rotor I. The inner faces ll of extensions I2 are straight, smooth and tangent to face I6. The inner end face I3 on each abutment I3 is straight, smooth and parallel to the adjacent face I1.

Each bridge 5 is slidably fitted in a recess I9, which is formed in spacer ring 3, and it is accurately and smoothly finished to such dimensions that it forms substantially liquid tight joints with the walls of recess I9 and with the inner faces of the cheek plates.

The inner face 20 of each bridge 9 is smoothly finished to a radius which may be equal to the distance between face 2B and the center of rotor I when bridge 9 is either in its zero displacement position, in its maximum displacement position or in an intermediate position but, for simplicity and economy in manufacture, it ordinarily is finished to the same radius to which the faces I 6 on bridges e are finished.

Bridges 9 may be shifted to and held .in adjusted positions in any suitable manner. As shown, each bridge 9 is provided with a recess 2| to receive the inner end of a control rod 22 which is fixed to bridge 9 by a pin 23 and extends radially outward through spacer ring 3. Control rods 22 are operated in unison by mechanism not shown.

Each track section I0 is integral at one end with a bridge 9, as previously explained, and its inner face is smooth and forms a continuation of the face 20 on bridge 9. The other or free end of each track section Ill is provided with a notch 24 (Fig. 6) to enable it to straddle an extension I2 on a bridge 8 and to be supported upon the faces I8 of the adjacent abutments I3 as shown in Figs. 1 and 2. Track sections II) ordinarily are initially bent to a radius enough greater than the radius of face 20 to cause the free ends thereof to remain in contact with faces I8 in all positions of bridge 9.

The free end of each section It is of a thickness exactly equal to the distance between a face 17 and the adjacent face I8. Therefore, since faces I? and I8 are parallel to each other, face I1 is substantially tangent to the inner face of track section It? at all positions of bridge 9, thereby providing a smooth path for each vane .5 as it passes from a bridge 8 onto a track section I0 and from a track section I!) onto a bridge 8.

In order to keep the radial accelerations .and decelerations of the vanes well within the permissible limits, each track section I 0 is gradually tapered from a maximum thickness at its free end to a minimum thickness adjacent bridge 9 to thereby cause the portion of track section I0 adjacent bridge 9 to hex more than the free end portion thereof a bridge 9 is moved toward and from rotor I.

The accelerations and decelerations of the vanes are greatest when bridges 9 are in their maximum displacement positions but, if track sections ID are properly proportioned, there will be no abrupt changes in the rates of acceleration and deceleration. For example, if the rotor is about three and one-half inches in diameter, the thickness of a track section at its thinnest part may be about ixty per cent of the thickness at the free end.

The arrangement is such that the vane track will be substantially concentric with the rotor and no significant radial movement of the vanes will occur when bridges 9 are in their zero displacement positions as shown in Fig. l but, when bridges 9 are moved outward from their zero displacement positions, each vane will startto move gradually outward as it passes from a face l6 onto a face I'l, it will gradually accelerate as it passes from that face H onto the adjacent track section Ill, it will continue to gradually accelerate until it reaches a point intermediate bridges 8 and 9 and then it will gradually decelerate until it passes onto the face 20 of the adjacent bridge 9. It will then have substantially no radial movement until it passes onto the next track section [0 and then it will start to move inward. It will gradually accelerate as it continues to move along track section l0, it will continue to gradually accelerate until it reaches a point intermediate the ends of section 10 and then it will gradually decelerate until it passes onto face l6 of the next bridge 8 and then radial movement of the vane will cease as the vane moves across face I6. There are thus no abrupt changes in rates of radial acceleration and deceleration of of the vanes and, consequently, abrasion of the ends of the vanes and of the van track i negligible.

Each bridge 9 and the two track sections I0 integral therewith may be formed from a blank which may be a rectangular bar 30, a indicated by dotted lines in Fig. 7, or which may be a forging of the general shape of but larger in all dimensions than the partly finished blank shown in full lines in Fig. '7.

If the blank is a rectangular bar, one side thereof may be machined to form two flat faces 3| which will later be ground to form the inner faces of the two track sections Ill. The same face of the bar i machined between the two faces 3| to form an arcuate face 32 which later will be ground to form the face of bridge 9.

The opposite side of bar 30 is machined at opposite sides of the center thereof to form a bridge part 9 which is slightly larger in all dimensions than the finished bridge 9, and to form two track section parts Ill which are slightly thicker than the finished track sections 10. A fillet 33 is then formed in bridge 3 contiguous to each track section part Ill and notches 24 are formed in the ends of track section parts Ill Faces 3| have been shown as being formed in alinement with each other but the blank may be machined to form the opposite faces 34 of track section parts w in alinement with each other in which case faces 3! are formed at such an angle to the axis of bridge part B that track section parts Ill will have the proper taper.

If the blank is of the general shape of but larger than the partly finished blank shown in full lines in Fig. 7, the operation will be the same as explained above but less stock will be removed.

Bridge part a may now be finished, as by grinding, to the proper size to enable it to have a close sliding fit between the side walls of recess I9 and between the two cheek plates or it may be finished to size after track section parts If! have been bent into arcuate form. Also, bridge part 9* may now be provided with a connection for the device which shifts it to and holds it in adjusted positions, such as by forming in it a recess 2| for rod 22 and a hole 35 for in 23.

After the blank has been machined to the shape shown in full lines in Fig. '7, it is heated to the proper temperature and then track section parts I 3 are bent while hot in suitable dies as shown diagrammatically in Fig. 8 in which the blank is shown clamped between a female die 36 and a male die 31.

The partly finished blank -ltl is preferably made of self-hardening steel, such as Airkool steel and it is left in the dies until it cools sumciently to reharden. It is then removed from the dies and heat treated to reduce the hardness to the desired degree such as Rockwell C60. The four fiat sides of bridge part 9 may then be finished, as by grinding, to theexact dimensions of bridge 9 and the two track section parts I0 may now be finished to a width which will permit them to move freely between the two cheek plates. 1

Face 32 on bridge part 9 and the inner faces 3| of track section parts Ill are then simultaneously finished, as by grinding to the correct radius. This is ordinarily accomplished by grinding the faces 3! and 32 of two of the nearly finished blanks with those two blanks'fastened in a fixture which corresponds to spacerring 3 and which holds the bridge parts 9 in, zero displacement position. The fixture has not been illustrated as a view thereof with the parts as-. sembled therein would be substantially the same as Fig. 1.

Preferably, the faces it of stationary bridges 3 are finished to the proper radius at the same time. This is accomplished by assembling two of the nearly finished blanks 9a.lil and. two sta tionary bridges 8 having unfinishedfaces. It in the fixture in substantially the same manner that they iare assembled in. spacerring. 3. as. shown. in Fig. 1, so that the parts thus assembled form a continuous vane track, and then grinding the inner face of the track to a radius whichexceeds the radius of rotor l by an amount equal to the clearance between rotor I and a face It of a stationary bridge 8. The parts may then be removed from the fixture as they are ready for assembly in a hydrodynamic machine.

The movable bridge 9 and integral track sections It shown in Fig. 5 may also be made from a rectangular blank 40 according to the method illustrated in Figs. 9 and 8. In this case, two fillets 33 are formed in opposite faces of blank 40 at the proper distance from one end of the blank and those two faces are machined from the other end of the blank to the fillets to form tapered faces 44 which correspond to the faces 34 of the partly finished blank shown in Fig. '7.

Then stock is removed to the proper width by a broaching, milling or other cutter from between the two faces 44 to form two track section parts Hl' and a bridge part 9 which correspond, respectively, to the track section parts Ili and bridge parts 9 shown in Fig. 7. The cutter used to remove the stock, or at least the cutter used to remove the last part of the stock, is ground to such a radius that it will form on bridge part 9 an arcuate face 42 which corresponds to the face 32 shown in Fig. 7. The partly finished blank 9 lll thus produced may be completed in the same manner that blank 9 lll is completed as explained above.

Vane tracks may be made very accurately and economically by the foregoing methods.

The invention herein set forth may be modified in various ways without departing from the scope thereof. The invention is hereby claimed as follows:

1. The method of making a part of a vane track, which includes a plurality of bridges spaced around a common center and flexible track sections arranged between adjacent bridges, comprising the steps of cutting a metal bar which is rectangular in cross-section to a given length, machining said bar to form a bridge part and two flexible track :sections which :extend :from near "adjacent corners of said bridge part, machining saidztrackszsections to taper the same so that they are substantially thinner adjacent said bridge part than at theiree ends thereof, machining the face of said bridge part between said track sections 'to a given.radius,rheating:said track sections and at least the adjacent portion of said bridge part, bending said track-sections while hot in a bending die to approximately said :radius, and cooling said track sections while in the bending die.

.2. "The method of making a part of a vane track, wwhichincludes a plurality-of bridges spaced around a common center and flexible track sections :arrangedbetween adjacent bridges, comprising the steps of forming Ifillets :in two opposite "sides of a bar which is rectangular in crosssection, machining said two sides fromsaid'flllets to one :end 'of .said ."bar .to slightly bevel the same so that said .bar is'widerat said one .end thanv ad- *jacent said fi1lets,:remov ing stock from between said two sides to form a bridge part and twofiexifble tracksection's which extend from-near opposite sides of sai'dibridge part and which are thinner adjacentsaid bridge part than at the free ends thereof, machining the face of said bridge part between said ltrack sections to a given radius, iheatingfsaid track sections :andat least the adjacent portion of said bridge part, "bending said track sections .while :hot in a bending die to approximately said radius, and cooling said track sections while in the bending die.

WALTER FERRIS.

REFERENCES CITED 'The following references are '01 record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,028,036 Lee May 28, 1912 1,318,811 Skelly Oct. 14, 1919 1,326;661 Hewitt Dec, 30, 1919 1,340,844 'Sonnichsen May 18, 1920 1,431,041 Rees Oct. 3, 1922 1,727,817 Evans Sept. .10, 1929 1,793,717 Pearson Feb. 24, 1931 1,938,203 Witherell Dec. 5, .1933 1,936,836 MacNeille Jan. 8, 1935 2,086,992 Weber July 13, 1937 2,079,077 Leuthesser May 4, .1937 2,126,200 Linderman Aug. 9,.1938 2,141,170 Centerval Dec. 27, 1938 2,145,864 Denneen Feb. 7, 1939 2,243,464 Kucher May 27, 1941 2,256,459 Kendrick Sept. 16, 1941 2,368,223 Kendrick Jan. 30, 1945 2,467,121 Ferris Apr. 12, 1949 

